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NCT Number: NCT07197554

A Phase 1/1B Study of ST-01156, a Small Molecule RBM39 Degrader, in Patients With Advanced Solid Malignancies

A Phase 1/1B Study of ST-01156 in Patients with Advanced Solid Malignancies

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Key information

Conditions

Advanced Solid Tumors Adenocarcinoma Biliary Tract Cancer (BTC) Biliary Tract Diseases Biliary Tract Neoplasms Carcinoma Carcinoma, Hepatocellular Digestive System Diseases Digestive System Neoplasms Endometrial Neoplasms Ewing Sarcoma Female Urogenital Diseases Female Urogenital Diseases and Pregnancy Complications Genital Diseases Genital Diseases, Female Genital Neoplasms, Female Hepatocellular Carcinoma (HCC) Liver Diseases Liver Neoplasms Neoplasms Neoplasms by Histologic Type Neoplasms by Site Neoplasms, Bone Tissue Neoplasms, Connective Tissue Neoplasms, Connective and Soft Tissue Neoplasms, Glandular and Epithelial Osteosarcoma Sarcoma Sarcoma, Ewing Urogenital Diseases Urogenital Neoplasms Uterine Diseases Uterine Neoplasms

Age range

16 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 1

Primary location

The City of Hope National Medical Center, Duarte, California, United States

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About this study

This Phase 1/1b study is evaluating the safety, tolerability, and preliminary anticancer activity of ST-01156 in participants with advanced solid malignancies. The study will be conducted in 2 parts. Part 1 (Dose Escalation) will assess the safety, tolerability, pharmacokinetics (PK) and preliminary anticancer activity of SD-01156 in participants with advanced solid malignancies, many of whom have a biological rationale to be targeted with an inhibitor of RBM39. Part 1 will also seek to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of ST-01156.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age ≥ 18 years on the day of signing the consent form, except for adolescents with Ewing Sarcoma or other malignancies for which there is a biological rationale to support participation, in which case the participant is ≥ 16 years old.
  • Has a metastatic or locally advanced and unresectable solid tumor.
  • Has at least 1 measurable lesion or evaluable disease per RECIST v1.1.
  • Has an ECOG performance status ≤ 2 at screening.
  • Has adequate organ function as defined in the protocol.

Exclusion criteria

  • Has received prior radiotherapy within 2 weeks of treatment.
  • Has known active CNS metastases and/or carcinomatous meningitis. Participants with previously treated brain metastases may participate, provided they are radiologically stable
  • Has received treatment with any local or systemic anticancer therapy or investigational anticancer agent within 14 days or 5 half-lives, whichever is shorter.
  • Had major surgery within 28 days before study therapy administration
  • Has toxicities from previous anticancer therapies that have not resolved to baseline levels, with the exception of alopecia and peripheral neuropathy.
  • Has previously received a RBM39 inhibitor/degrader.

Treatment and study plan

ST-01156

Drug

ST-01156 is an orally administered degrader of RBM39, a protein frequently upregulated in cancer

Primary outcomes

  1. Part 1: Dose Escalation

    Time frame: First 28 days of treatment

    To characterize the safety, tolerability, and adverse event (AE) profile of escalating doses of ST-01156 administered for 5 consecutive days followed by 2 days without study drug administration every 7 days, with a cycle defined as 28 days (4 weeks).

  2. Part 1: Dose Escalation

    Time frame: Duration of treatment period

    To identify the maximum tolerated dose (MTD) or maximum administered dose (MAD), and to recommend a dose for subsequent studies (recommended Phase 2 dose [ RP2D]) of ST-01156 on a daily oral schedule for 5 consecutive days out of every 7 days with a cycle defined as 28 days (4 weeks).

Secondary outcomes

  1. Part 1: Dose Escalation

    Time frame: First 28 days of treatment

    To characterize the pharmacokinetics (PK) of ST-01156 administered on a daily oral schedule for 5 consecutive days every 7 days with cycle defined as 28 days (4 weeks). PK parameters will include area under the concentration-time curve (AUC), maximum observed concentration (Cmax), and time to observe maximum observed concentration (Tmax).

  2. Part 1: Dose Escalation

    Time frame: Baseline and every 6 weeks thereafter until disease progression

    To detect preliminary evidence of antitumor activity in select advanced cancers where strong preclinical evidence of the anticancer activity of RBM39 degradation is strongest including:

    • Adults or adolescents with ES following disease progression or intolerance to therapeutics of reasonable likelihood of conferring clinical benefit.
    • aHCC following disease progression or intolerance to appropriate standard therapy for advanced disease.
    • KRASm solid malignancy of any type - locally advanced or unresectable solid malignancy following disease progression or intolerance to therapeutics or reasonable likelihood of conferring clinical benefit.
    • BTC, endometrial carcinoma, solid malignancies with pathogenic somatic or germline mutations in BCRA1/2 or HRR genes (BRCA1/2, PALB2, RAD51C, RAD51D, ATM, BARD1, BLM, BRIP 1, CDK12,FANCA, FANCC, FANCD2, FANCE, FANCF, FANCM, MRE11A, NBN (NBS1), RAD50, RAD51B and others as confirmed by a Clinical Laboratory Improvement Amendments [CLIA]-certified m

Other outcomes

  1. Part 1: Dose Escalation

    Time frame: Days 1, 2, 3, 4, 5, 8, 15, and 16 of the first two 28-day cycles of treatment, and days 1 of subsequent cycles, until permanent discontinuation of study treatment.

    To evaluate the relationship between RBM39 degradation in peripheral blood mononuclear cells (PBMC) [and potentially other cells or tissues], to various safety and efficacy endpoints.

Study contacts

Contact information is provided by the study sponsor or research team.

Dr. Eric Rowinsky Chief Medical Officer

CONTACT

[email protected]

(908) 883-0647

Sponsors and collaborators

Lead sponsor

SEED Therapeutics, Inc.

Industry

Registry information

Important dates

Study start
2025
Primary completion
2029
Study completion
2029
First posted
Sep 29, 2025
Registry last updated
Jun 2, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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